Reporting on environmental indicators - 2018

Air Quality and Emissions

Organic Pollutants in Air

Significance

Organic pollutants, such as flame retardants and pesticides, are human-made chemicals that may contaminate ecosystems. Wind and water can carry these chemicals away from their sources to reach places like the Arctic, where they have never been used before. They tend to settle in colder climates and once deposited, can enter arctic ecosystems. Many of these contaminants are toxic and can accumulate in the food chain, affecting the health of wildlife and humans.

Measuring how much organic pollutants are present in arctic air over time will provide us with information on:

whether their concentrations are decreasing, increasing or not changing over time;

where these chemicals have come from;

how much of each chemical comes from which region; and

what climate conditions influence their movement to the Arctic.

This information can inform policies that limit emissions and hopefully reduce what comes into the Arctic. Results about how organic pollutant concentrations change in air can be used to negotiate and evaluate the effectiveness of domestic and international control agreements and to assess the risks of new contaminants. The results are also used to test atmospheric models that explain contaminant movement from sources in the South to the Arctic.

What is happening?

Air samples have been continuously collected at the Little Fox Lake Station in Yukon since August 2011.

The detection of these chemicals in the remote subarctic site of Little Fox Lake demonstrates their long range transport through air and suggests that they could contribute to the chemical contamination of remote areas such as the Arctic.

The air concentrations of two pesticides, hexachlorocyclohexane and endosulfan, are decreasing at Little Fox Lake.

Measurement results show that globally regulated flame retardants (e.g., some of the polybrominated diphenyl ethers) have declined from 2012 to 2014. Canada regulated these flame retardants in 2008 and they have been regulated globally since 2009.

Conversely, 10 new flame retardants that are not currently regulated were frequently detected in air at Little Fox Lake (Figure 1).

Air samples taken at Little Fox Lake in 2015 and 2016 are currently undergoing chemical analysis to investigate if the concentrations of new flame retardants are changing with time.

Figure 1: (a) Regulated flame retardants at Little Fox Lake showed declining tendency from 2012 to 2014. (b) Flame retardants found in air in Little Fox Lake that are currently not regulated (Yu et al. 2015).

In warm seasons, organic pollutants tend to stem from potential sources in Northern Canada, the Pacific and East Asia. In cold seasons, they mainly came from the Pacific Rim. One example of this is a new flame retardant called 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (Figure 2).

Figure 2: Maps showing potential source regions for one of the new flame retardants detected at Little Fox Lake, 2-ethylhexyl 2,3,4,5-tetrabromobenzoate. The maps indicate that (a) in the warm seasons most of this chemical observed at Little Fox Lake stemmed from sources in Canada, the Pacific and East Asia; (b) in cold seasons they mainly came from the Pacific Rim. Black dots on map show potential paths of movement of wind carrying this chemical reaching Little Fox Lake.

Taking action

The federal Northern Contaminants Program has measured organic pollutants in air in Yukon since 1992 during three short term studies at Tagish (December 1992 to March 1995) and Little Fox Lake (July 2002 to July 2003 and August 2007 to October 2009).

Continuous measurements are now conducted at Little Fox Lake since August 2011 to determine:

if the air concentrations are declining for chemicals that are under domestic and international regulations, showing these regulations are effective;

where these chemicals have come from, and how much from which region; and

if new chemicals that are currently not under control can be carried to Yukon by wind.

The Little Fox Lake data are provided to support the Stockholm Convention on Persistent Organic Pollutants — a global treaty to protect human health and the environment from the adverse effects of these pollutants. Signatories to the convention work towards controlling how much and what kind of persistent organic pollutants humans release into the environment.

These data also support the Arctic Council’s Arctic Monitoring and Assessment Programme that provides information on the status and threats to the Arctic environment, and provide scientific advice on actions to be taken to support Arctic governments in their efforts to take remedial and preventive actions relating to contaminants.